1. Department of Oral and Diagnostic Sciences, Faculty of Dentistry, Bayero University, Kano, Nigeria
2. Department of Oral Pathology, Radiology, and Medicine, College of Dentistry and Dental Clinics, The University of IA, Iowa City, IA, USA
3. Department of Preventive and Community Dentistry, College of Dentistry and Dental Clinics, The University of Iowa, Iowa City, IA, USA